Aircraft: LARGE TRANSPORT
Phase of flight: Final Approach
Anomaly: ATC Issue All Types; Conflict Airborne Conflict; Deviation - Speed All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy

I was working AR-V for my first session of the morning. We were in the middle of a small traffic 'bump.' Conditions on the approach were ideal. Excellent visibility; aircraft slowing predictably inside the marker with little compression. Aircraft X was cleared for the visual approach to follow traffic. At 10 miles; I noticed he was a little slower to bleed speed off than the other aircraft; so instead of using 180 knots as I normally do; I slowed him to 170 to build an extra 1/2 mile. Spacing was fine; so I switched him to tower (I believe) 'at AJAAY' (the FAF). I noticed his speed slow to 140 knots across the ground. I told Aircraft X to 'don't cheat; I need 170 knots to the FAF.' There was no answer. I called the LC responsible for the runway and said Aircraft X either needed to do the assigned 170 knots to the FAF or he needed to turn to a 360 heading and climb to 4000. He sped up. Behind him was Aircraft Y. Thinking he would be heavy and a little faster inside the FAF; I told them Aircraft X had slowed early but I had extra room behind him. I told him speed was his discretion and switched him to tower. Behind Aircraft Y was Aircraft Z. Aircraft Z was 5+ in trail of Aircraft Y. We use RECAT at ATL. I'm allowed in IFR conditions to use 3.5 in trail of this type aircraft. When volume is light; I typically try to get closer to the old standard of separation. I told Aircraft Z what happened ahead of him and also offered him additional speed reduction if he wanted it. Aircraft Z was on a visual approach following the traffic; so while I could let that compress to the point the lead aircraft barely clears the runway; I don't do that. After Aircraft Z; I had 4 miles in trail; so I was back to normal at that point. I was relieved for a scheduled break shortly after this. At ATL; we have high speed taxiways that are built at ideal places. It's not unusual to have aircraft 1.5 in trail and both land. We've had awful problems with [Aircraft X and Z company] not complying with ATC instructions. When [Company] came to ATL; they told us how they were going to fly their airplanes. Well; at the busiest airport in the world; we'll do what we can; but it's about efficiency of all users; and if that means 180 knots instead of 170 knots to the FAF; then that's what we need. Today; however; was blatant and affected not just the two airplanes behind; but my sequence behind him. I advised the supervisor of the situation; and I believe they were going to 'talk' to the crews. I say the time to 'talk' is past. If [company] is going to do whatever they want; it's time to start sending a message that when an ATC clearance is received you do it. If you can't; you ask for something else. You don't just do it and not tell anyone what you're doing. Violating the pilots is the last option. I don't like resorting to that; but [company] leaves us few other options. [Company] is not the only user at Atlanta. They need to comply with instructions and yield to the way we do business. We've done it for quite a while and we're pretty good at it. A80 Controller describes a situation where an aircraft slows; slower than the assigned speed and causes problems for traffic that is following.